Alnylam wins two orphan designations for hemophilia RNAi drug

RNA interference (RNAi) drug-delivery specialist Alnylam ($ALNY) won two orphan drug designations this week and last, both for the same drug--one designation is for hemophilia A and the other for hemophilia B. Alnylam's RNAi drugs use small pieces of the genetic code to silence, or turn off, genes that cause diseases.

The FDA granted orphan status to Alnylam's ALN-AT3, a subcutaneous antithrombin for rare bleeding disorders. In July, the company presented preclinical data supporting the effectiveness of the drug in normalizing thrombin generation, which stems blood loss, and improving hemostasis in mice, according to Alnylam. In primates, ALN-AT3 fully corrected thrombin generation. The company expects to begin a Phase I clinical trial in early 2014 if approved by the U.S. agency.

The trouble with RNAi-based drugs, the discovery of which was awarded a 2006 Nobel Prize, has been with the delivery of the genetic material, but Alnylam's GalNAc conjugate delivery platform, which allows for effective subcutaneous injection of the drug, makes it possible to target specific diseases. Getting the small interfering RNA particles past several barriers into the cells' genetic machinery can be a challenge.

With the orphan status of ALN-AT3, Alnylam is on its way to reaching its goal of having five RNAi drugs in clinical development by the end of 2015. Its furthest candidate, ALN-TTR--to treat TTR-mediated amyloidosis--recently completed a successful Phase II study, and the company plans to begin a pivotal Phase III study by the end of 2013.

"As a subcutaneously delivered RNAi therapeutic, we believe (ALN-AT3) represents an innovative approach for the management of hemophilia and has great potential to make meaningful impact in the treatment of this often debilitating bleeding disorder," Alnylam's senior vice president of regulatory affairs and quality assurance, Saraswathy Nochur, said in a statement. "We look forward to advancing this promising RNAi therapeutic into the clinic in the months to come."

A patient with hemophilia has trouble developing thrombins, which are enzymes that form blood clots; hemophilia A is the most common type.

- here's the hemophilia A release
- and here's the hemophilia B release